Mapping Henry: Dendrochronological Analysis Of A Sixteenth-Century Panel Painting Based Upon Synchrotron-Sourced X-Ray Fluorescence Mapping

The study of materials that comprise artworks significantly contributes to understanding of age and provenance. While dendrochronology is a particularly valuable and well-established technique for panel paintings comprising oak timber, conventional practices of resurfacing end-grains to reveal tree rings is becoming less acceptable because it removes material, modifying the painting. Recently, application of non-destructive X-ray fluorescence (XRF) spectroscopy to a portrait of Henry VIII held by the Art Gallery of New South Wales (AGNSW), Sydney, Australia revealed tree-ring boundaries in the resulting high-resolution elastic scatter XRF map. In this study, we examine the dendrochronological potential of that mapping with the aim of contributing to resolving the relationship of the AGNSW portrait to similar paintings elsewhere. Examination of the timber revealed affinities with Quercus petraea (Matt.). We measured tree-ring widths along multiple paths in the XRF scatter map and crossdated the resulting 81-year XRF ring-width (XRF (portrait) ) series against master chronologies of English, western European, and Baltic origin. Rather than an arbitrarily defined threshold, we used a Bonferroni correction to determine a minimum significance level for crossdating. While the XRF (portrait) series did not crossdate with the continental European chronologies, we identified a single significant (alpha = 3.4 x 10(-6)) dating position with the English chronology (1400-1480 CE). Cross-matching with site-level chronologies revealed a cluster of high t-values in central-southern England. The earliest date of felling precedes the documented date of completion for the AGNSW and two similar Tudor portraits of Henry VIII held by the National Portrait Gallery (NPG), London and one at the Society of Antiquaries, London. While the apparent British provenance of timber used in the AGNSW portrait contrasts to Baltic origin of timbers used for the two NPG portraits and the majority of English panel paintings, it is consistent with the provenance of the timber used for the Society of Antiquaries portrait.